Warning lamp assembly having means to test bulb



Dec. 16, 1969 a. J. BUTTERF'IELD v 3,484,

WARNING LAMP ASSEMBLY HAVING mums T0 wmsw Buns Filed April 13, 19s? 3,484,783 WARNING LAMP ASSEMBLY HAVING MEANS T TEST BULB Geolrrey John Butterfield, Burnley, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England, a British company Filed Apr. 13, 1967, Ser. No. 630,672 Claims priority, application Great Britain, May 27, 1966, 23,925/ 66 Int. Cl. G08b /00, 23/00; G09f 9/00 U.S. Cl. 340-366 4 Claims ABSTRACT OF THE DISCLOSURE A warning lamp having a casing housing the warning lamp bulb is disclosed. A part is movable on the casing to complete a circuit through the bulb to test the bulb.

This invention relates to warning lamp assemblies particularly, but not exclusively intended for use in road vehicles.

In a warning lamp assembly, the bulb is energised only when a predetermined undesirable condition subsists, and so it is desirable to test the bulb periodically to ascertain whether or not it is in working order. It is an object of the present invention to provide a lamp assembly wherein such periodic testing is facilitated.

A warning lamp assembly according to the invention comprises a casing, first, second and third terminals carried by the casing, a resilient conductive strip within the casing, the strip being connected to the first terminal and adapted to support a bulb with the bulb in contact with the second terminal so that a circuit between the first and second terminals is completed through the bulb, and a movable part supported by the casing and adapted to move the strip into contact with the third terminal, the arrangement being such that in use the second terminal is connected to one side of a DC. source, the third terminal is connected to the other side of the DC. source, so that operation of said movable part tests the bulb, and the first terminal is connected to said other side of the D0. source through a switch which closes when a warning is to be given.

One example of the invention is illustrated in the accompanying drawings wherein:

FIGURE 1 is a plan view of a warning lamp assembly, and

FIGURE 2 is a sectional view on the line 22 in FIG- URE 1 showing diagrammatically the electric circuits associated with the assembly.

Referring to the drawings there is provided a generally rectangular, open box like casing 11 which is moulded in synthetic resin and the base 12 of which is laterally stepped at 13. Extending perpendicularly within the casing 11 from the portion 13 of the base is a post 14 having a conductive resilient strip 15 secured thereto by a conductive rivet 16, the arrangement being such that the strip 15 is aligned longitudinally of the casing 11 and is generally parallel with the base 12. The rivet 16 serves to connect the strip 15 electrically to a terminal 17 on the exterior of the base 12.

The casing further supports a pair of terminals 21, 22 connected to the casing by rivets 18, 19 respectively. The strip 15 is formed near one end with a hole 23, the edge of which is shaped to constitute a single convolution of a screw thread. A bulb 24 is engaged with the strip 15 and the arrangement is such that the contact 25 on the base of the bulb engages the rivet 18-. The end of the strip 15 remote from the hole 23 supports a contact 26 at a position spaced from but adjacent the contact 19.

" United States Patent 0 A cover 27 also moulded in synthetic resin closes the casing 11 and is pivotally engaged therewith for rocking movements about a lateral axis. For this purpose the cover is formed with a pair of integral lugs which snap into holes in the casing. A projection 28 integral with the cover 27 extends perpendicularly therefrom into engagement with the strip 15 close to the contact piece 26.

Part of the cover 27 is formed with a hole which is closed in use by an appropriately coloured, translucent, synthetic resin lens 31 through which the bulb is observed. The end of the cover remote from the lens 31 being formed with. a plurality of laterally extending ribs 32.

In use, the assembly is secured to the dash board of the road vehicle so as to be visible to the driver of the vehicle. The terminal 22 is connected directly to one terminal of the vehicle battery, the terminal 17 being connected to the same terminal through a switch 33. The terminal 21 is connected to earth.

When the switch 33 is closed, the bulb is energised. The switch 33 could, for example, close to indicate a low fluid level in a brake fluid reservoir.

In order to test the lamp the cover 27 is pivoted in a direction to cause the projection 28 to flex the strip 15 thereby engaging the contact 26 with the rivet 19 and completing a circuit from the battery through the strip 15 and the bulb to earth. The ribs 32 on the cover 27 facilitate gripping the cover. Upon release of the cover it will be returned to its original position due to the resilience of the strip 15.

Co-acting stop means (not shown) are provided on the cover and the casing to prevent the cover being inadvertently pivoted in the wrong direction.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A Warning lamp assembly comprising a casing, first, second and third terminals carried by the casing, a resilient conductive strip within the casing, the strip being connected to the first terminal and adapted to support a bulb with the bulb in contact with the second terminal so that a circuit between the first and second terminals is completed through the bulb, and a movable part supported by the casing and adapted to move the strip into contact with the third terminal, the arrangement being such that in use the second terminal is connected to one side of a DC. source, the third terminal is connected to the other side of the DC. source, so that operation of said movable part tests the bulb, and the first terminal is connected to said other side of the DC. source through a switch which closes when a warning is to be given.

2. A warning lamp assembly as claimed in claim 1 wherein said movable part includes a non-opaque window through which the bulb is visible in use.

3. A warning lamp assembly as claimed in claim 1 wherein the movable part is pivotally supported on the casing, pivotal movement of said part in one direction serving to complete the electrical circuit through the econd and third terminals.

4. A warning lamp assembly as claimed in claim 3 wherein stop means are provided to prevent pivotal movement of the movable part other than in a direction to complete the electrical circuit through the second and third terminals.

References Cited UNITED STATES PATENTS 2,925,592 2/1960 Noyes 340381 X HAROLD I. PITTS, Primary Examiner U .8. Cl. X.R. 

